The cranial morphology of an Anolis lizard preserved in Dominican amber, observed using pseudo-three-dimensional reconstructed images derived from high resolution X-ray computed tomography (CT) data, demonstrates the lack of a splenial in the lower jaw. The specimen is referred to T-clade anoles, the clade that includes the A. chlorocyanus species group, to which two other Dominican anoles in amber have been referred. The pattern of bone breakage and loss suggests trauma followed by decomposition prior to entombment. The trunk-crown ecomorph of A. chlorocyanus species group anoles was established on what was to become Hispaniola between approximately 33 and 20 million years ago.

About the Species

Excerpted from Polcyn et al. (2002):

The specimen, SMU 74976, was donated to the Shuler Museum of Paleontology at Southern Methodist University (SMU) by William S. Lowe of Granbury, Texas, who discovered it in a commercial shipment of amber containing plant and insect inclusions. The amber originated in the Dominican Republic, but was purchased through a broker without precise locality data. Dominican amber deposits are considered to be late Early to early Middle Miocene in age, approximately 15-20 million years old (Iturralde-Vinent and MacPhee 1996).

Preserved elements include a relatively complete skull, portions of the first six cervical vertebrae, some soft tissue, and limited squamation. The posterior-most vertebra is exposed to the polished amber surface; the remaining portion of the fossil is completely encapsulated. Because of the exposure of an articulated vertebra on the surface of the amber, we assume the fossil was originally more complete (e.g., not preserved only as a head and neck), but that the loss of an undetermined amount of the body occurred between fossilization and curation.

This specimen was scanned by the University of Texas High-Resolution X-ray CT Facility for Dr. Lou Jacobs of Southern Methodist University and Dr. Mike Polcyn of the Institute for the Study of Earth and Man. Funding for image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of The University of Texas at Austin

About this Specimen

This specimen was scanned by Richard Ketcham on 20 July 1998 along the coronal axis for a total of 148 slices. Each slice is 0.06 mm thick, with an interslice spacing of 0.06 mm and a field of reconstruction of 4.5 mm.

Etheridge, R. 1959. The relationships of the anoles (Reptilia: Sauria: Iguanidae): an interpretation based on skeletal morphology. Ph.D. dissertation, University of Michigan, Ann Arbor, Michigan, USA.

Graham, A. 1992. The current status of the legume fossil record in the Caribbean region, p. 161-167. In P.S. Herendeen and D.L. Dilcher (eds.), Advances in Legume Systematics. The Royal Botanic Gardens, Kew.

Kobayashi, K., D. A. Winkler, and L. L. Jacobs. 2002. Origin of the tooth-replacement pattern in therian mammals: evidence from a 110 Myr old fossil. Proceedings of the Royal Society of London B 269:369-373.